Syntheses and crystal structures of two new complexes based on R-isophthalate (R = -CH3 or -OCH3) and bis(imidazole) Co-ligand

Article abstract of DOI:10.1080/15533174.2012.749900

Two new complexes, [Co(CH₃-ip)(biim-5)]_n (1) and [Co(CH₃O-ip)(biim-5)]_n (2) (CH₃-H₂ip = 5-methylisophthalate, CH₃O-H₂ip = 5- methoxyisophthalate, biim-5 = 1,5-bis(imidazole)pentane), have been synthesized via hydrothermal reactions and characterized by elemental analysis and single-crystal X-ray analysis. Complex 1 belongs to the monoclinic system, P2(1)/c space group, a = 9.464(2) A, b = 14.567(4) A, c = 15.206(4) A, β = 102.369(2)°, F (000) = 916, R₁ = 0.0701, wR₂ = 0.1831; complex 2 belongs to the monoclinic system, P2(1)/c space group, a = 9.5922(17) A, b = 15.231(3) A, c = 16.3797(19) A, β = 122.638(7)°, F (000) = 948, R₁ = 0.0466, wR₂ = 0.1188. In the two complexes, CH₃-ip and CH ₃O-ip both adopt bis-monodentate bridging modes to link neighboring Co(II) ions to form 1D chains, which are further across-linked by biim-5 ligands to generate 2D (4,4) rectangular grid layers. These identical 2D single nets are interlocked with each other and form an interesting threefold parallel interpenetrated architecture. Copyright Taylor and Francis Group, LLC.

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Syntheses and Crystal Structures of Two New
Complexes Based on R-isophthalate (R = –CH3 or –OCH3)
and bis(imidazole) Co-ligand
Jian-Hua Qin a , Jian-Ge Wang a , Ke-Yan Zhao a & Yue Hu a
a College of Chemistry and Chemical Engineering , Luoyang Normal University , Luoyang , P.
R. China
Accepted author version posted online: 07 Feb 2013.Published online: 07 Mar 2013.
To cite this article: Jian-Hua Qin , Jian-Ge Wang , Ke-Yan Zhao & Yue Hu (2013) Syntheses and Crystal Structures of Two New
Complexes Based on R-isophthalate (R = –CH3 or –OCH3) and bis(imidazole) Co-ligand, Synthesis and Reactivity in Inorganic,
Metal-Organic, and Nano-Metal Chemistry, 43:5, 647-651, DOI: 10.1080/15533174.2012.749900
To link to this article: http://dx.doi.org/10.1080/15533174.2012.749900
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Synthesis and Reactivity in Inorganic, Metal-Organic, and Nano-Metal Chemistry, 43:647–651, 2013
Copyright ꢀ Taylor & Francis Group, LLC
C
ISSN: 1553-3174 print / 1553-3182 online
DOI: 10.1080/15533174.2012.749900
Syntheses and Crystal Structures of Two New Complexes
Based on R-isophthalate (R = –CH3 or –OCH3) and
bis(imidazole) Co-ligand
Jian-Hua Qin, Jian-Ge Wang, Ke-Yan Zhao, and Yue Hu
College of Chemistry and Chemical Engineering, Luoyang Normal University, Luoyang, P. R. China
rigid or flexible N-donor ligands, such as 4,4ꢁ-bipyridine and its
derivatives, and bis(imidazole) ligands, have been designed and
characterized widely.[13–19] In order to further investigate the
influences of the flexibilities of the ligands on the architectures
of coordination polymers, in this study, we chose 5-methylisop-
hthalate (CH3-H2ip), 5-methoxyisophthalate (CH3O-H2ip), and
1,5-bis(imidazole)pentane (biim-5) to construct new coordina-
tion polymers. Herein, we present the preparation and crystal
structures of two Co(II) complexes: [Co(CH3-ip)(biim-5)]n (1)
and [Co(CH3O-ip)(biim-5)]n (2)
Two new complexes, [Co(CH3-ip)(biim-5)]n (1) and [Co(CH3O-
ip)(biim-5)]n (2) (CH3-H2ip = 5-methylisophthalate, CH3O-H2ip =
5-methoxyisophthalate, biim-5 = 1,5-bis(imidazole)pentane), have
been synthesized via hydrothermal reactions and characterized by
elemental analysis and single-crystal X-ray analysis. Complex 1 be-
longs to the monoclinic system, P2(1)/c space group, a = 9.464(2)
Å, b = 14.567(4) Å, c = 15.206(4) Å, β = 102.369(2)◦, F (000) = 916,
R1 = 0.0701, wR2 = 0.1831; complex 2 belongs to the monoclinic
system, P2(1)/c space group, a = 9.5922(17) Å, b = 15.231(3) Å,
c = 16.3797(19) Å, β = 122.638(7)◦, F (000) = 948, R1 = 0.0466,
wR2 = 0.1188. In the two complexes, CH3-ip and CH3O-ip both
adopt bis-monodentate bridging modes to link neighboring Co(II)
ions to form 1D chains, which are further across-linked by biim-5
ligands to generate 2D (4,4) rectangular grid layers. These iden-
tical 2D single nets are interlocked with each other and form an
interesting threefold parallel interpenetrated architecture.
EXPERIMENTAL
Materials and Physical Measurements
All reagents used in the syntheses were of analytical grade.
Elemental analyses for carbon, hydrogen, and nitrogen were
performed on a Vario EL III elemental analyzer (Elementar
Analysensysteme GmbH, Germany). The crystal determination
was performed on a Bruker SMART APEX II CCD diffrac-
tometer (Germany) equipped with graphite-monochromatized
MoKα radiation (λ = 0.71073 Å).
Keywords 1, 5-bis(imidazole)pentane), 5-methoxyisophthalate,
5-methylisophthalate, crystal structure
INTRODUCTION
The design and synthesis of metal-organic frameworks
(MOFs) have attracted considerable attention because of their
potential applications as functional materials as well as their
structural diversity and intriguing variety of topologies.[1–8]
Usually, structure-directing ligands, coordination geometries
of metal ions and the reaction conditions are the main keys to
achieve the construction of charming structural topologies. As
to organic ligands, carboxylate ligands have attracted intensive
research interest due to their various coordination modes to
metal ions, allowing for the large diversity of topologies.[9–12]
So far, a great many metal-carboxylate complexes containing
Syntheses of Complexes
[Co(CH3-ip)(biim-5)]n (1)
A mixture of CH3-H2ip (0.1 mmol, 18.0 mg), biim-5
(0.10 mmol, 20.4 mg) and Co(OAc)2·4H2O (0.1 mmol, 24 mg),
KOH (0.1 mmol, 5.6 mg), and distilled water (15 mL) was
placed in a Teflon-lined stainless steel vessel, heated to 120◦C
for three days, and then cooled down to room temperature over
24 h. Red block crystals of 1 were obtained. Elemental analysis
(%): Anal. Calcd. for C20H22CoN4O4 (Mr = 441.35): C, 54.43;
H, 5.02; N, 12.69; Found: C, 54.48; H, 4.98; N, 12.65.
Received 16 May 2012; accepted 11 November 2012.
This work was supported by the Henan tackle key problem
of science and technology (No. 112102310528 and 102102210246)
and the Foundation of Education Committee of Henan province
(No. 2011B150023).
Address correspondence to Jian-Hua Qin, College of Chemistry and
Chemical Engineering, Luoyang Normal University, Luoyang 471022,
P. R. China. E-mail: jh q128105@126.com
[Co(CH3O-ip)(biim-5)]n (2)
2 was synthesized in a similar way as that described
for 1, except that CH3-H2ip was replaced by CH3O-H2ip
(0.1 mmol, 19.2 mg). Elemental analysis (%): Anal. Calcd. for
C20H22CoN4O5 (Mr = 457.35): C, 52.52; H, 4.85; N, 12.25;
Found: C, 52.49; H, 4.82; N, 12.29.
647

648
J.-H. QIN ET AL.
TABLE 1
Crystallographic data for complexes 1 and 2
Compounds
1
2
Empirical formula
Formula weight
Temperature (K)
Crystal system
C20H22CoN4O4
441.35
296(2)
C20H22CoN4O5
457.35
296(2)
Monoclinic
Monoclinic
Space group
P2(1)/c
P2(1)/c
Unit cell dimensions
a = 9.464(2) Å
b = 14.567(4) Å
c = 15.206(4) Å
β = 102.369(2) ◦
2047.7(8)
a = 9.5922(17) Å
b = 15.231(3) Å
c = 16.3797(19) Å
β = 122.638(7) ◦
2015.2(6)
V (Å3)
Z
4
4
Dc (Kg·m−3
)
1.432
916
1.507
948
F(000)
GOF
1.057
1.076
Crystal size (mm3)
0.43 × 0.39 × 0.36
2.33∼25.50
14599
0.25 × 0.19 × 0.17
2.51∼25.49
14993
θ range for data collection (◦)
Reflections collected
Independent reflections
Final R indices (I > 2σ(I))
R indices (all data)
Largest diff. peak and hole (e Å−3
3693(Rint = 0.0378)
R = 0.0701, wR2 = 0.1831
R = 0.0786, wR2 = 0.1908
1.791 and –0.566
3748 (Rint = 0.0493)
R = 0.466, wR2 = 0.1188
R = 0.0677, wR2 = 0.1306
0.671 and –0.373
)
placement factors and included in the final refinement by use of
geometrical restrains. A full-matrix least-squares refinement on
F2 was carried out using SHELXL-97.[22] The final R = 0.0701,
Crystallographic Data Collection and Structural
Determination
Single-crystal X-ray diffraction analyses of the two
complexes were carried out on a Bruker SMART APEX II
CCD diffractometer (Germany) equipped with a graphite-
monochromated MoKα radiation (λ = 0.71073 Å) by using
the ϕ/ω scan technique at room temperature. The structures
were solved by direct methods with SHELXS-97.[20] Empirical
absorption corrections were applied with SADABS program.[21]
All non-hydrogen atoms were refined anisotropically. The
hydrogen atoms were assigned with common isotropic dis-
wR = 0.1831 (w = 1/[σ2(Fo ) + (0.0355P)2 + 2.0850P], where
2
2
2
P = (Fo + 2Fc )/3), S = 1.057, ( ρ)max = 1.791 and ( ρ)min
= –0.566 e/Å3 for 1; R = 0.0466, wR = 0.1188 (w = 1/[σ2(Fo )
2
+ (0.0673P)2 + 0.4338P], where P = (Fo + 2Fc )/3), S =
1.076, ( ρ)max = 0.671 and ( ρ)min = –0.373 e/Å3 for 2.
Table 1 shows the crystallographic crystal data of 1 and 2, and
Table 2 shows their selected bond lengths and bond angles.
2
2
RESULTS AND DISCUSSION
Crystal Structure Description
[Co(CH3-ip)(biim-5)]n (1)
The X-ray structural analysis shows that 1 crystallizes in a
monoclinic system, space group P2(1)/c. The asymmetric unit
of 1 consists of one Co(II) ion, one CH3-ip ligand, and one
biim-5 molecule. The Co(II) ion adopts a tetrahedral coordi-
nation geometry, coordinating to two carboxylic O atoms from
two CH3-ip ligands (Co1–O1 = 1.949(3) Å and Co1–O3B =
1.941(3) Å) and two N atoms from two biim-5 ligands (Co1–N1
= 2.017(4) Å and Co1–N4A = 2.013(4) Å), as depicted in
Figure 1. The CH3-ip in 1 shows a bis-monodentate coordina-
tion mode for the two carboxyl groups, bridging the neighboring
Co(II) ions to yield a 1D straight chain.
FIG. 1. Coordination environment of the Co(II) ion in 1. Symmetry codes: A
x, 3/2 – y, –1/2 + z; B –1 + x, y, z.

5-METHOXYISOPHTHALATE, 5-METHYLISOPHTHALATE
649
TABLE 2
Selected bond lengths (Å) and bond angles (◦) for 1 and 2
Compound 1
Bond
Dist.
Bond
Dist.
Co(1)-O(3)#1
Co(1)-O(1)
1.941(3)
1.949(3)
Co(1)-N(4)#2
Co(1)-N(1)
2.013(4)
2.017(4)
Angle
(◦)
Angle
(◦)
O(3)#1-Co(1)-O(1)
O(3)#1-Co(1)-N(4)#2
O(1)-Co(1)-N(4)#2
112.34(14)
112.59(16)
108.49(15)
O(3)#1-Co(1)-N(1)
O(1)-Co(1)-N(1)
N(4)#2-Co(1)-N(1)
96.33(16)
117.46(16)
109.30(15)
Compound 2
Bond
Dist.
Bond
Dist.
Co(1)-O(3)#1
Co(1)-O(1)
1.971(2)
1.973(2)
Co(1)-N(1)
Co(1)-N(4)#2
2.018(3)
2.020(3)
Angle
(◦)
Angle
(◦)
O(3)#1-Co(1)-O(1)
O(3)#1-Co(1)-N(1)
O(1)-Co(1)-N(1)
113.74(11)
96.78(12)
114.55(11)
O(3)#1-Co(1)-N(4)#2
O(1)-Co(1)-N(4)#2
N(1)-Co(1)-N(4)#2
112.36(12)
107.43(11)
111.89(12)
Symmetry transformations used to generate the equivalent atoms: #1 x – 1, y, z; #2 x, –y + 2/3, z – 1/2 for 1 and #1 x – 1, y, z; #2 –x + 1, y +
1/2, –z + 1/2 for 2.
The adjacent chains are further bridged by biim-5 lig- with the dihedral angle between the two imidazole rings of
ands to form a 2D (4,4) layer (Figure 2), showing a rect- 62.341(2)◦.
angular window with the dimensions of 9.464 × 14.162 Å2.
The (4,4) layers stack parallel along the b direction with an
ABAB sequence, and each of these equivalent layers is in-
terpenetrated with the adjacent two parallel layers exhibit-
ing overall 2D → 3D polycatenations (Figure 3). The biim-
5 molecule adopts a bidentate-bridging conformation mode
[Co(CH3O-ip)(biim-5)]n (2)
As shown in Figure 4, the structure of 2 contains one Co(II)
ion, one CH3O-ip ligand, and one biim-5 molecule.
Each Co(II) ion is in a distorted tetrahedral geometry. The
four atoms coordinated to Co(II) ion come from two oxygen
FIG. 2. 2D layer of 1 connected by CH3-ip and biim-5 ligands.
FIG. 3. Schematic representation of the 2D → 3D polycatenation of 1.

650
J.-H. QIN ET AL.
CONCLUSIONS
Two new complexes have been synthesized under
hydrothermal conditions by the reaction of Co(II) salt,
5-methylisophthalate, and 5-methoxyisophthalate with the
introduction of flexible N-donor ancillary ligand. The two
complexes both manifest a highly corrugated 2D (4,4) layer,
which are penetrated by each other to give rise to 3D polycate-
nations. The change of noncoordinating group on the aromatic
backbone from methy to methoxy group does not exert a
significant impact on the final structures. Further systematic
studies for the design and syntheses of such polymers with
polycarboxylate and bis(imidazole) ligands are underway in our
laboratory.
SUPPLEMENTARY MATERIALS
FIG. 4. Coordination environment of the Co(II) ion in 2. Symmetry codes: A
–1 + x, y, z; B 1 – x, 1/2 + y, 1/2 – z.
Crystallographic data for the structural analysis have been
deposited with the Cambridge Crystallographic Data Centre,
CCDC No. 829885 and 829886. Copies of this information may
be obtained free of charge on application to CCDC, 12 Union
Road, Cambridge CB2 1EZ, UK (fax: +44–1223-336–033; E-
mail: deposit@ccdc.cam.ac.uk or http://www.ccdc.cam.ac.uk).
atoms of two CH3O-ip ligands, (Co1–O1 = 1.973(2) Å and
Co1–O3B = 1.971(2) Å), two nitrogen atoms of two biim-5
ligands, (Co1–N1 = 2.018(3) Å and Co1–N4A = 2.020(3) Å).
Each CH3O-ip ligand adopts a bis-monodentate bridging mode
to link neighboring Co(II) ions to form a 1D chain, which is
further bridged by biim-5 ligands to generate a 2D (4,4) rect-
angular grid layer (Figure 5). The identical 2D single nets are
interlocked with each other and form an interesting threefold
parallel interpenetrated architecture. The Co···Co nonbonding
distances across the CH3O-ip ligand and the biim-5 molecule are
9.592 and 13.192 Å, respectively. The biim-5 molecule adopts a
bidentate-bridging conformation mode with the dihedral angle
between the two imidazole rings of 58.173(8)◦. The structure of
2 is very similar to that of 1.
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